Airplane



March 11, 1941. I TANK 2,234,883

' AIRPLANE Filed Oct. 5, 19559 2 Sheets-Sheet l ZQELZMBBIB K. TANK AIRPLANE March 11, 1941.

Filed Oct. 5, 1.939 2 Sheets-Sheet 2 Patented Mar. 11, I941 UNlTED STATES PATENT OFFICE Wulf Fluneugbau G Flughafen, Germany m. IL, Bremen- Applicatlim gctobcr 5, 1939, Serial No. 298,131

n ermany October I, 1938 2 Claims. (01. 244-42) This invention relates to airplanes and has special reierence to auxiliary or extension wings for airplanes.

More particularly the invention relates to aux- 5 iliary wings adapted to extend rearwardly from the trailing edges of the main wings or aerofoils.

Heretofore, it has been customary, when such auxiliary wings were used, to provide an air flow space between the trailing edge of the main wing and the leading edge of the auxiliary wing to prevent interruption of stream line air flow over the upper surfaces of the main and auxiliary wings due to the formation of eddy currents at the trailing edge of the main wing. 'I'heprovision of such an air gap is satisfactory in those cases in which the angle of attack of the auxiliary wing approximates the angle of attack of the main wing, but in modern aircraft with greater loads and higher landing speeds than formerly, it has become necessary in many cases to use an angle of attack for the auxiliary wing considerably greater than that of the main wing, so that a considerable angularity exists between v the upper surfaces of the main andauxiliary wings when the latter are extend In such cases, the customary air gap is found insufllcient to prevent the formation of eddy currents interfering with the stream line air flow.

One important object of the present invention is to provide an improved means for preventing the formation of eddy currents at the trailin edge of the main wing while the auxiliary wings are extended.

A second important object of the invention is to pro de a novel arrangement of suction openings and devices in the main wings for preveniw ing such eddy currents.

A third important object of the invention is to provide a novel arrangement of auxiliary wing 40 ior controlling air flow through such openings.

A fourth. important object of the invention is to provide a novel arrangement of auxiliary wing wherein the leading edge of such wing is, when extended, overlapped by the trailing edge of the main wing.

A fli-th important object of the invention is to provide a novel arrangement of mainand auxilmy wings, wherein the auxiliary wing is housed in the underside of the main wing whennot in use, and wherein means are provided for moving the auxiliary wing into extended position, such means being further arranged to effect angular adjustment of the auxiliary wing to vary the angle of attack as d with the above and other objects in view, as

will be presently understood, the invention consists in general of certain novel details of construction and combinations of pants hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the 5 appended claims.

In the accompanying drawings, like characters of reference indicate like parts in the several views, and-- Figure 1 is a bottom plan view of an airplane 10 wing with an auxiliary wing in housed relation therein as constructed in accordance with this invention.

Figure 2 is a similar view but showing the auxiliary wing extended. 15 Figure 3 is a bottom plan view of a portion of a main wing with the auxiliary wing removed to better show the suction openings.

Figure 4 is a section on the line ure 1.

Figure 5 is a section on the line 5-5 of Figure 2.

In the form of the there is illustrated a 4-4 of Figinvention here disclosed, main airplane wing in of any preferred stream line cross section. This 2 wing is provided with an upper surf-ace ii and a lower surface l2, and has its trailing edge indicated at l3. In the underside of the wing Ill, there is formed a convex pocket I for the reception of an auxiliary wing, indicated in general 30 at IS. The pocket I has its rear edge close to but spaced slightly from the trailins'e ge l3. The auxiliary wing has an upper side having its forward portion l6 constituting a plane surface and its rear portion 11 curved to form a stream 35 line surface terminating forwardly at the rear edge of the plane portion 16 and rearwardly at the trailing edge I8. The under surface is of the wing I5 is comparatively flat to lie, with the wing housed, flush with the under surface I! of 4 the main wing l0 and forms a smooth and unbroken continuation of such under surface l2, as can beseen by reference to Figure 4.

At eachside of the wing I5 there is provided an arm 20. which is pivoted at 2! to the main 45 wing l0, adjacent the trailing edge It. These arms are also pivoted to the auxiliary wing l5 at 22, the point 22 being preferably at the aerodynamic center of the wing l5. As shown in Figures 4 and 5, these arms support the wing 50 from movement between housed and extended Positions, and the pivotal connection at 22 permits angular variation in the position of the wing i5, so that it may be caused to have a desired angle of attack. The means for swinging 55 the arms 20 and tack will be hereinafter described.

It will be seen from Figure 5, that the trailing As shown in Figure 4, the trailing edge portion I of the wing l5 closes the openings upon hous ing 01' the wing. However, when the wing is extended rearwardly, as in Figure 5, the leading edge contacts the inside of the pocket just forwardly of the openings 23 and the surface |6 inclines rearwardly and downwardly to form a wedge-shaped passage 28, through which air is induced to flow by the partial vacuum in the chamber 24,-and this effectually breaks up the in efficiency of the auxiliary wing.

In order to operate the auxiliary wing IS, the pivot 2| may be in the form of a shaft extending transversely of the airplane and having the arms 20 fixed thereon. 0n the shaft 2| is also fixed a worm wheel 29, wherewith meshes a worm 30, suitably journalled' as at 3| and 32. the worm is a pulley 33, around which extends a belt or wire 34, which passes to any common operating means (not shown) suitably positioned Fixed to 2,234,888 foradiusting the angle of a-tin he airplane- By actuating the belt or wire 34, the worm 30 is rotated and this causes rotation of the wheel 29 and shaft 2| so that the arms 20 are swung to house or extend the auxiliary wing l5.

To vary the angle of attack or pitch of the auxiliary wing |5, the pivot 22 may be fixed to the wing and joumalled in the free end of the On the pivot 22 is fixed a pulley which is connected by a belt 36 pulley 31 rotatably mounted on the shaft 2|. A crank provided pulley 38 is suitably mounted in the airplane and is connected by a belt 38 with the double pulley 31. By operating the crank of the pulley 38, the latter is-rotated and in turn causes rotation of the pulleys l1 and 35 so that the'wing I! may be tilted to any desired position.

What I claim is:

1. In an aircraft, a main wing having a trailing edge portion and provided with a. pocket in its under side adjacent said trailing edge, an auxiliary wing normally fitting in said pocket, and means to move the auxiliary wing from the pocket wing without disturbing the air flow over the wings, and means for creating a suction effect in the main wing to remove the boundary layer at the suction side of this uninterrupted profile.

auxiliary wing registers smoothly and flush against the under surface of the main wing.

KURT TANK. 

